| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an LED lighting device capable of achieving improvement in accuracy of color temperature control. <P>SOLUTION: In the LED lighting device, chromaticity points Wa, Wb, Wc of each light-emitting device 1a, 1b, 1c are so set to satisfy a relation that: a straight line connecting a chromaticity point Wc of a blue-color system light-emitting device 1c and a chromaticity point Wb of a green-color light-emitting device 1b in an xy chromaticity diagram of an XYZ color system passes a chromaticity point W<SB>1</SB>of a high-temperature end (7,000 K in an illustrated example) of a desired color temperature adjustment range regulated on a blackbody locus BL; a straight line connecting a chromaticity point Wa of a red-color system light-emitting device 1a and a chromaticity point Wb of the green-color system light-emitting device 1b passes a chromaticity point W<SB>2</SB>of a low-temperature end (2,500 K in an illustrated example) of the color temperature adjustment range; and a straight line connecting the chromaticity point Wc of the blue-color system light-emitting device 1c and the chromaticity point Wa of the red-color system light-emitting device 1a is at a side with a value of y smaller than a line connecting the chromaticity points W<SB>1</SB>, W<SB>2</SB>at either end of the color temperature adjustment range in a direction along a y-axis of the chromaticity coordinate. <P>COPYRIGHT: (C)2010,JPO&INPIT |
